Difference between $() and ``

[oleg9419]

Hello,
Are these 2 different ?

content=`cat file`

content=$(cat file)

when I echo them out , I receive the same result , but does shell handle them
the same ? or not ?

Thanks

[keskiverto]

Which shell? Bash?

Read section "Command substitution" from

man bash

[oleg9419]

If you could tell me for both that would be great

[keskiverto]

I just did.

I will not copy text here, because you are better off by learning to read the manual.

Note: man-pages are online too, if you don't have them installed.

[ShodanHo]

They are identical in bash.
Google: Advanced Bash Scripting

[koothkeeper]

In the Korn shell, the grave accents style ('') is obsolete. It's also slower than $().

[keskiverto]

http://www.gnu.org/software/bash/manual/bashref.html#Command-Substitution writes:

When the old-style backquote form of substitution is used, backslash retains its literal meaning except when followed by ‘$’, ‘`’, or ‘\’. The first backquote not preceded by a backslash terminates the command substitution. When using the $(command) form, all characters between the parentheses make up the command; none are treated specially.

Command substitutions may be nested. To nest when using the backquoted form, escape the inner backquotes with backslashes.

I.e. not identical.